Natural hybridization and potential seed set of sympatric Populus nigra and Populus x canadensis along the river IJzer in Flanders

Background In Europe, Populus nigra generally grows sympatric with the exotic related taxon Populus x canadensis. Natural hybridization followed by introgression and genetic swamping is often mentioned as a potential threat for the conservation of P. nigra. However, as evidence for natural hybridization with P. x canadensis is scarce, the significance of this threat is unclear. Methods After first determining the genotypic diversity within 209 trees of P. nigra collected in western Flanders (northwest Belgium), we assessed natural hybridization events between P. nigra females and P. x canadens... Mehr ...